Plastic encapsulated electronic devices have gained increased acceptance as a result of advantages in size, weight, cost, availability, performance, and state of-the-art technology and design. Nevertheless, one drawback of some plastic encapsulated devices is the stress imparted by the mold material on the die. The pressure can result in various reliability problems, including passivation and passage crack, as well as metal displacement.
Some of the reliability issues can be addressed through the use of low stress molding compounds. Nevertheless, the plastic encapsulation stress can cause parametric shifts in devices from the time of wafer sort until post packaging. Such shifts can cause components to shift outside of device specifications, post packaging, and may increase yield loss, or may require further testing and trimming.